My secondary dictionary is strictly a pronunciation dictionary, although it does have some definitions; it goes into some depth as to where the sound is produced in the mouth or throat, and has many examples and detailed symbology. This was originally published in 1932, and is of the Glengarry Dialect.
Dieckhoff, Henry Cyril. A Pronouncing Dictionary of Scottish Gaelic. Glasgow: Gairm Publications, 1998. (ISBN: 1871901189)